I recall seeing a thread about this last year I believe. I just wanted to add a warning. I had small rocks in two bags of diamond crystal splash ready pool salt that I bought at lowes. I have bought pool salt from them for years and I believe it has always been diamond crystal but I'm not certain. Regardless I have never had this problem before. These were large enough that I believe they could have damaged my liner if left. I threw the largest ones away before I thought to take a picture. The largest were about 5 times the size of the biggest ones in the photo I took.